CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Siqin Liu,Zhaoxia Li,Qiangliang Yu,Yuming Qi,Zhenjun Peng,Jun Liang
In this work, a new self-healing composite coating for corrosion protection of magnesium (Mg) alloy, which is based on the dual actions of the corrosion inhibitor M-16 embedded in the micro-arc oxidation (MAO) coating and self-healing polyurethane (PU) modified by disulfide bonds, is developed. Electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) are used to study the anti-corrosion performance of the scratched and healed composite coatings immersed in 3.5 wt% NaCl solution. Results show that the porous MAO coating is suitable to carry inhibitor M-16 and the anti-corrosion performance of the scratched coating is significantly improved by the inhibitor embedded in the MAO coating. The scratched coating exhibits an excellent recovery of the anti-corrosion performance after the heat treatment, which is attributed to the cooperation of dynamic disulfide bonds and shape-memory effect of the self-healing PU coating. Furthermore, it is found that the inhibitor M-16 embedded MAO coating can enhance the repair ability and anti-corrosion performance of the PU coating when the corrosion product was pre-formed inside the scratch of the composite coating.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
Methods in Enzymology
·
2024
·
IF 1.682
Xingming Pan,Liao-Bin Dong
Magnesium ions (Mg 2+ ) are crucial in class II terpene cyclases that utilize substrates with diphosphate groups. Interestingly, these enzymes catalyze reactions without cleaving the diphosphate group, instead initiating the reaction through protonation . In our recent research, we discovered a novel class II sesquiterpene cyclase in Streptomyces showdoensis . Notably, we determined its crystal structure and identified Mg 2+ within its active site. This finding has shed light on the previously elusive question of Mg 2+ binding in class II terpene cyclases. In this chapter, we outline our methods for discovering this novel enzyme , including steps for its purification , crystallization , and kinetic analysis.
研究领域:
生物化学
·
结构生物学
✓ 已验证
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
·
2018
·
IF 1.686
Huaiwei Zhang,Jianbo Qi,Zhenguo Ji
Synergic effects of rare earth-magnesium based hydrides (LaH 3 -MgH 2 ) on thermal dehydrogenation of potassium borohydride (KBH 4 ) are discussed in the paper. Comparing to above 675 K for the LaH 3 -MgH 2 or KBH 4 , the dehydrogenation temperature can be decreased to 346 K for the composites (LaH 3 -MgH 2 -KBH 4 ). The apparent activation energy of desorption process for the mixture is also greatly reduced. On the other hand, the products in the temperature programmed desorption process are also illustrated.
研究领域:
材料化学
·
无机化学
·
能源材料
·
储氢材料
·
固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Cong Peng,Yongtao Li,Qingan Zhang
Magnesium hydride is a promising hydrogen storage material and how to improve its sorption kinetics is one of challenges in practical applications. In this paper, a new approach is proposed to catalyze MgH 2 with highly dispersed Ni nanoparticles by in-situ hydrogenolysis of nickelocene (NiCp 2 ) in ball milling process. After ball milling under 4 MPa hydrogen atmosphere for 15 h, the MgH 2 –16.1 wt% NiCp 2 sample exhibits a homogeneous morphology where the in-situ formed Ni nanoparticles with size of ~8 nm are highly dispersed in MgH 2 matrix. During initial dehydrogenation , Ni would react with MgH 2 to form Mg 2 Ni which inherits the configuration of its high dispersion. In the subsequent hydrogen absorption and desorption cycles, the much fine and highly dispersed Ni-based catalytic phase contributes to the superior hydrogen desorption kinetics of MgH 2 with a high-capacity retention rate of ~96% after 50 cycles. This work demonstrates that the in-situ formation of highly dispersed catalytic species is beneficial for improving hydrogen storage properties of MgH 2 .
研究领域:
材料科学
·
无机化学
·
能源化学
·
纳米催化
·
氢储能
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
·
2019
·Vol. 31
·期 10
·04019237
·
IF 1.984
Yongshan Tan,Hongfa Yu,Wanli Bi,Nan Wang,Na Zhang
A new type of material, magnesium oxysulfate cement (MOSC), has attracted widespread attention as an environmentally friendly and low-energy inorganic green cementitious material due to its outstanding performance. In this study, electrochemical impedance spectroscopy (EIS) and in situ X-ray diffraction (XRD) were used to characterize the hydration behavior and process of MOSC. EIS was also used to investigate the effect of fly ash (FA) on the hydration behavior of MOSC. Mercury intrusion porosimetry (MIP), backscattered scanning electron microscopy (BSE), and scanning electron microscopy (SEM) were used to study the evolution of the pore structure and micromorphology of MOSC incorporated with FA. The results show that the resistance values (?1) in the equivalent circuit for MOSC increase with increasing curing time. The incorporation of FA can affect the resistance values for each element in the equivalent circuit. In the early stages of hydration (1 day and 2 days), high-volume FA can reduce the degree of hydration of MOSC paste. At the later stages of hydration, the resistance values (?1) increase with increasing FA content. The MIP, BSE, and SEM results also show that the porosity of MOSC decreases with increasing FA content; the incorporation of FA can significantly improve the morphology of MOSC, resulting in a denser microstructure. This study shows that the electrochemical impedance spectroscopy is a powerful technique to investigate the hydration behavior and process of MOSC, and the results also indicate that FA is a good mineral admixture used as a partial substitute for MOSC cementitious materials.
研究领域:
材料科学
·
硅酸盐工程
·
建筑材料
·
无机非金属材料
·
绿色建材
✓ 已验证
DOI
高影响因子
AUSTRALIAN JOURNAL OF CHEMISTRY
·
2018
·Vol. 71
·期 6
·416-421
·
IF 1.059
Ouyang Dong,Zhihong Zhang,Zhenhai Fu,Xiang Li
A new phase-change material (PCM) CaCl2·6H2O + MgCl2·6H2O + NH4Cl was investigated in this paper. MgCl2·6H2O and NH4Cl were mixed with CaCl2·6H2O to obtain CaCl2·6H2O as a eutectic hydrate salt. The results show that the eutectic composition of the PCM is as follows: 90 wt- % CaCl2·6H2O, 6.25 wt- % MgCl2·6H2O and 3.75 wt- % NH4Cl; the undercooling degree is less than 1.5°C when the nucleating agent is 2 wt- % SrCl2·6H2O or 1.5 wt- % Ba(OH)2·8H2O. The phase-change temperature and latent heat are respectively 25.3°C and 144.3 J g−1 when the composition is 90 wt- % CaCl2·6H2O, 6.25 wt- % MgCl2·6H2O, 3.75 wt- %, NH4Cl, with 2 wt- % SrCl2·6H2O as nucleating agent, and 2 wt- % carboxymethyl cellulose as thickener. In addition, when the composition is changed to 90 wt- % CaCl2·6H2O, 6.25 wt- % MgCl2·6H2O, 3.75 wt- % NH4Cl, 1.5 wt- % Ba(OH)2·8H2O and 2 wt- % carboxymethyl cellulose, the phase change temperature and latent heat are 25.2°C and 139.3 J g−1, respectively.
研究领域:
材料科学
·
热能存储
·
化学工程
✓ 已验证
DOI
高影响因子
Materials Science & Engineering C-Materials for Biological Applications
·
2013
·Vol. 33
·期 8
·5044-5050
·
IF 2.404
Y.H. Xia,B.P. Zhang,C.X. Lu,L. Geng
In this paper, corrosion resistance of the Mg–4.0Zn–0.2Ca alloy was modified by micro-arc oxidation (MAO) process. The microstructure and phase constituents of MAO layer were characterized by SEM, XRD and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of MAO treated Mg–4.0Zn–0.2Ca alloy in the simulated body fluid were characterized by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The microstructure results indicated that a kind of ceramic film was composed by MgO and MgF 2 was formed on the surface of Mg–4.0Zn–0.2Ca alloy after MAO treatment. The electrochemical test reveals that the corrosion resistance of MAO treated samples increase 1 order of magnitude. The mechanical intensity test showed that the MAO treated samples has suitable mechanical properties.
研究领域:
生物医学工程
·
材料科学
·
生物材料
·
表面工程
·
腐蚀科学
✓ 已验证
DOI
高影响因子
APPLIED PHYSICS LETTERS
·
2024
·Vol. 124
·期 9
·
IF 3.5
Zhou Pengfei,Zhang Pengcheng
The Li 2 Mg 3 Ti 1 − x Al 4 x /3 O 6 (0 ≤ x ≤ 0.1) ceramics are synthesized using the solid phase method, showing excellent microwave dielectric properties with ε r = 14.05, Q × f = 144 500 GHz, and τ f = −43 ppm/°C at x = 0.04. Rietveld refinements, based on the XRD data, reveal that the Li 2 Mg 3 Ti 1 − x Al 4 x /3 O 6 ceramics crystallize in the rock salt structure with Fm-3m space group. The relationship between the crystal structure and intrinsic microwave dielectric properties is studied in detail. The variation in the dielectric constant is related to ionic polarization and relative density. The quality factor (Q × f) demonstrates a strong correlation with lattice energy, relative density, and concentration of Ti 3+ . The variation of τ f is influenced by the bond thermal expansion coefficient and bond valence. The dielectric resonant antenna, manufactured from Li 2 Mg 3 Ti 0.96 Al 0.0533 O 6 -0.09TiO 2 ceramic with near-zero τ f , shows a bandwidth of 230 MHz at 7.40 GHz and a high radiant efficiency, which indicates that high-quality factor Li 2 Mg 3 Ti 0.96 Al 0.0533 O 6 ceramic has significant potential in relevant fields such as 5G and smart driving.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
POLYMER COMPOSITES
·
2017
·Vol. 39
·期 10
·3676-3685
·
IF 2.324
Juan Gong,Weihong Guo,Kai Wang,Jiaoyang Xiong
In order to enhance the adhesion and compatibility of magnesium hydroxide sulfate hydrate (MHSH) whiskers with polyvinyl chloride (PVC), and prepare high performance MHSH/PVC composites, chitosan (CS) is coated on the surface of MHSH whiskers by a facile method. The effect of the CS-coated MHSH (CS-MHSH) whisker and its toughness and reinforcement for PVC are studied. A thin layer coated on the surface of MHSH whiskers after modification is investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The efficacy of surface modification is confirmed by fourier transform infrared spectroscopy (FTIR), X-ray power diffraction analyses (XRD) and energy disperse spectroscopy (EDS). The optimum modification concentration of CS is 0.025%. The notched impact strength and flexural modulus of PVC composite with 15 phr CS-MHSH whiskers are increased by 85.5% and 58.5% compared with those of pure PVC, and by 48.3% and 4.1% compared with those of the PVC composite with 15 phr unmodified MHSH whiskers. A better thermal stability of CS-MHSH/PVC composite is showed by thermogravimetric analysis (TGA). Dynamic mechanical analysis (DMA) result indicates that CS-MHSH whiskers have a better dispersion and a stronger interfacial adhesion with PVC matrix. POLYM. COMPOS., 39:3676–3685, 2018. © 2017 Society of Plastics Engineers
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Xiaohui Lu,Xinglin Yang,Jie Kong,Jianye Su,Quanhui Hou
One of the most important technologies for the sustainable development of energy in the future is solid-state hydrogen storage. This study employed etching methods to fabricate two-dimensional layered catalyst Mo 2 Ti 2 C 3 MXene, which was compared with unetched MAX phases Mo 2 Ti 2 AlC 3 and Ti 3 C 2 , as well as Mo 2 C. Through mechanical ball milling, these materials were mixed with MgH 2 to prepare composite materials, including MgH 2 + Ti 2 C 3 , MgH 2 + Mo 2 C, MgH 2 + Mo 2 Ti 2 AlC 3 , and MgH 2 + Mo 2 Ti 2 C 3 . According to the study, Mo 2 Ti 2 C 3 demonstrates the synergistic catalytic actions of Ti and Mo in contrast to Ti 2 C 3 and Mo 2 C. The composite material MgH 2 + Mo 2 Ti 2 C 3 lowers the initial dehydrogenation temperature of MgH 2 to 180 °C, which is 165 °C lower than pure MgH 2 . After 30 min at 250 °C, the dehydrogenation amount is approximately 5.85 wt%. Hydrogen absorption begins at 40 °C and reaches approximately 5.75 wt% at 150 °C. Additionally, it maintains a reversible hydrogen storage capacity of up to 96 % even after 20th cycles at 300 °C. This is because Mo 2 Ti 2 C 3 has one less layer of Al than Mo 2 Ti 2 AlC 3 , which results in a wider interlayer spacing, more active sites for MgH 2 , and facilitates hydrogen molecule dissociation and recombination.
研究领域:
材料科学
·
能源存储
·
催化
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Songlin Wang,Nan Jiang,Yanyan Liu,Yan Hao,Qiying Zhang,Hongying Niu,Jianji Wang
Methyl phenyl carbonate (MPC) is a versatile carbonate, particularly as an important component in the lithium-ion battery industry. Recently the green synthesis of carbonates from non-toxic feedstocks and efficient catalysts have attracted a considerable amount of interest but the development of a highly active catalyst for this synthesis is a great challenge. Herein, novel Pb-Mg thin nanosheet catalysts with high specific areas and large pore volumes were developed by one-pot hydrothermal approach for the synthesis of MPC without using any solvent. The nanosheets were thoroughly characterized by SEM-EDS, TEM , XPS , NH 3 -TPD, XRD , BET, and H 2 -TPR techniques. It is shown that a diphenyl carbonate (DPC) conversion of 56.6% and an MPC selectivity of 98.8% are achieved by a Pb-Mg nanosheet catalyst with 15 wt% Pb. The activity and selectivity values are significantly higher than the previous best value reported by using transition metal-based catalysts. After the reaction, the nanosheets can be separated by simple centrifugation and can be reused many times without a significant loss of catalytic activity, showing excellent stability and recyclability. A possible mechanism was investigated based on these results. This work provides new insight into accomplishing the efficient and green synthesis of MPC and offers a strategy for synthesizing other asymmetric carbonates.
研究领域:
化学工程
·
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
SURFACE ENGINEERING
·
2024
·
IF 2.4
Jie Qin,Wenhui Yao,Liang Wu,Fusheng Pan
To enhance anti-corrosion property of AZ31 magnesium alloys, slippery liquid-infused porous surfaces (SLIPSs) were prepared on benzoate-intercalated Mg-Al layered double hydroxides (LDHs). The typical morphology of SLIPSs was determined using a scanning electron microscope, and the successful loading of benzoate ions was confirmed by an X-ray diffractometer (XRD). Especially, this work focused on revealing how hydrothermal time affected the resistance to corrosion of SLIPSs. The electrochemical results indicated that when the hydrothermal duration was 24 h, the developed SLIPS exhibited remarkably improved corrosion resistance accompanied by the lowest corrosion current density of 2.5 × 10−3 μA cm−2. Furthermore, the results of immersion test demonstrated the superiority of SLIPSs in anti-corrosion durability. Based on the obtained results, the prepared SLIPSs can be promising candidates for the improvement in anti-corrosion performance of magnesium alloys.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）